void main(List<String> args) {
  try {
    dynamic name = 'tom';
    // 加了dynamic，调用变量的任何不存在的属性或方法，在编译期不报错，但运行时会报错
    name.aa();
    print(name.age);
  } catch (e) {
    print("发生异常" + e.toString());
  } finally {
    print('finally');
  }

  try {
    String str = 'Tom';
    if (str == 'easue') {
      print('ok');
    } else {
      throw Exception('找错人了');
    }
  } catch (e) {
    print(e);
  }
}
